WO2011085549A1

WO2011085549A1 - Method and apparatus for channel information feedback and precoding

Info

Publication number: WO2011085549A1
Application number: PCT/CN2010/070159
Authority: WO
Inventors: 陈晋辉; 李栋
Original assignee: 上海贝尔股份有限公司; 阿尔卡特朗讯
Priority date: 2010-01-13
Filing date: 2010-01-13
Publication date: 2011-07-21
Also published as: US20120300702A1; CN102474389B; CN102474389A; EP2525521A1; EP2525521A4; US8817634B2

Abstract

The present invention provides a technical scheme in a wireless communication system user terminal for feeding back downlink channel information (which is called explicit feedback) to a base station, and a technical scheme that the base station, according to the downlink channel information fed back from the user terminal, precodes the data to be sent to the user terminal. The user terminal, according to a downlink channel transmission matrix, the number of the downlink data streams, a space correlation matrix of multiple transmission antennas in the base station and a predefined codebook, determines an approximate equivalent matrix of the downlink channel transmission matrix, then feeds back the relevant information of the approximate equivalent matrix to the base station. The base station, according to the relevant information of the approximate equivalent matrix fed back from the user terminal, recovers the approximate equivalent matrix, and uses the approximate equivalent matrix to precode the downlink data to be sent to the user terminal.

Description

用于信道信息反馈及预编码的方法及装置技术领域 Method and device for channel information feedback and precoding

本发明涉及用于信道信息反馈及预编码的方法和装置。背景技术 The present invention relates to a method and apparatus for channel information feedback and precoding. Background technique

在 LTE-Advanced无线通信***中，对于 FDD MIMO***，为了获取较高的下行链路频谱效率，用户终端向基站反馈预编码码字以用于基站对待发送至用户终端的信号进行预编码，该方法称为暗示反馈 ( implicit feedback )，即用户终端根据下行信道传输矩阵来确定预编码码字，并将该码字反馈给基站。目前 Intel、华为等公司已经提出了利用现有规范中定义的预编码码书来进行一阶相关自适应的暗示反馈技术方案， "相关自适应" 的含义是指利用下行信道空间相关矩阵来改造预定义的码书， "阶" 的含义是指基站中待发送的数据流数。但该类暗示反馈技术方案仅适用于一阶的情形，对于多阶的情形， ***性能急剧恶化。因此，对于多阶的 FDD MIMO无线通信***，迫切需要一种可行的相关自适应的反馈方案。发明内容 In an LTE-Advanced wireless communication system, for an FDD MIMO system, in order to obtain a higher downlink spectral efficiency, the user terminal feeds back a precoding codeword to the base station for precoding the signal to be sent by the base station to the user terminal, The method is called implicit feedback, that is, the user terminal determines the precoding codeword according to the downlink channel transmission matrix, and feeds the codeword to the base station. At present, Intel, Huawei and other companies have proposed a first-order adaptive adaptive hint feedback technology scheme using the precoding codebook defined in the existing specification. The meaning of "correlated adaptation" refers to the transformation using the downlink channel spatial correlation matrix. A predefined codebook, the meaning of "order" refers to the number of data streams to be transmitted in the base station. However, this type of implies that the feedback technique is only applicable to the first-order case, and the system performance deteriorates sharply in the case of multiple orders. Therefore, for multi-order FDD MIMO wireless communication systems, a feasible and adaptive adaptive feedback scheme is urgently needed. Summary of the invention

本发明提出了一种无线通信***用户终端中用于向基站反馈下行信道信息（称为明示反馈， explicit feedback ) 的技术方案，以及基站根据用户终端反馈的下行信道信息，来对待发送至用户终端的数据进行预编码的技术方案。 The present invention provides a technical solution for feeding back downlink channel information (called explicit feedback) to a base station in a user terminal of a wireless communication system, and the base station sends the downlink channel information to the user terminal according to the downlink channel information fed back by the user terminal. The data is pre-coded for technical solutions.

本发明的发明思想是用户终端基于基站至其下行信道传输矩阵及基站中多个发送天线的空间相关矩阵来反馈下行信道信息给基站。在本发明中，下行信道信息为基站至用户终端间的下行信道传输矩阵的一个近似等效矩阵。 The inventive idea of the present invention is that the user terminal feeds back the downlink channel information to the base station based on the base station to its downlink channel transmission matrix and the spatial correlation matrix of the plurality of transmitting antennas in the base station. In the present invention, the downlink channel information is an approximate equivalent matrix of the downlink channel transmission matrix between the base station and the user terminal.

根据本发明的一个具体实施例，提供了一种在无线通信网络的用户终端中用于向基站反馈下行信道信息的方法，其中，包括以下步骤：获取所述基站至所述用户终端之间的下行信道传输矩阵；根据所述下行信道传输矩阵、下行数据流数、所述基站中多个发送天线的空间相关矩阵和预定码书来确定所述下行信道传输矩阵的一个近似等效矩阵；将所述近似等效矩阵的相关信息反馈给所述基站。 According to a specific embodiment of the present invention, a method for feeding back downlink channel information to a base station in a user terminal of a wireless communication network is provided, which includes the following steps: Obtaining a downlink channel transmission matrix between the base station and the user terminal; determining, according to the downlink channel transmission matrix, the number of downlink data streams, a spatial correlation matrix of multiple transmitting antennas in the base station, and a predetermined codebook An approximate equivalent matrix of the downlink channel transmission matrix; feeding back related information of the approximate equivalent matrix to the base station.

在一个实施例中，用户终端根据所述下行信道传输矩阵和所述下行数据流数来确定所述下行信道传输矩阵的一个等效矩阵，该等效矩阵为 mxN_t的二维矩阵，其中 m为下行数据流数， N_t为基站中发送天线的个数；然后根据所述等效矩阵、所述下行数据流数、所述空间相关矩阵和所述预定码书来确定所述近似等效矩阵，所述近似等效矩阵为 mxN_t的二维矩阵。 In an embodiment, the user terminal determines an equivalent matrix of the downlink channel transmission matrix according to the downlink channel transmission matrix and the number of downlink data streams, where the equivalent matrix is a two-dimensional matrix of mxN _t , where m For the number of downlink data streams, N _t is the number of transmitting antennas in the base station; and then determining the approximate equivalent according to the equivalent matrix, the number of downlink data streams, the spatial correlation matrix, and the predetermined codebook A matrix, the approximate equivalent matrix being a two-dimensional matrix of mxN _t .

在一个实施例中，用户终端对下行信道传输矩阵 H进行奇异值分解得 H = U∑V^H, 然后取所述奇异值分解得到的右侧酉奇异矩阵 V的共轭转置矩阵 V^H的前 m行向量作为所述等效矩阵， H = ；或者取所述奇异值分解得到右侧酉奇异矩阵 V的共轭转置矩阵 V^H的前 m行向量与对角矩阵∑的前 m列且前 m行中的 mx m个元素组成的对角矩阵∑_m的乘积作为所述等效矩阵 #， H =∑ 在一个实施例中，用户终端根据以下公式来确定所述近似等效矩阵^: = i?，其中， ?为所述基站中多个发送天线的空间相关矩阵，表示矩阵的转置， ^^argmax, ,薩„ *)}，其中， ^为所述预定码书中的码字，为 N_tx m 的二维矩阵，表示矩阵 ^的共轭， abs(HRW;)表示对矩阵 f}RW: 中的各个元素进行取模操作， trace{abs{HRW')}表示矩阵 abs(HRW')的迹，阵/^ *的弗罗贝

In an embodiment, the user terminal performs singular value decomposition on the downlink channel transmission matrix H to obtain H = U ∑ V ^H , and then takes the conjugate transpose matrix V ^H of the right 酉 singular matrix V obtained by the singular value decomposition. The first m row vector is used as the equivalent matrix, H = ; or the singular value decomposition is obtained to obtain the front m row vector of the conjugate transpose matrix V ^H of the right 酉 singular matrix V and the first m column of the diagonal matrix ∑ And the product of the diagonal matrix ∑ _m composed of mx m elements in the first m rows as the equivalent matrix #, H = ∑ In one embodiment, the user terminal determines the approximate equivalent matrix according to the following formula ^ : = i?, where ? is a spatial correlation matrix of a plurality of transmit antennas in the base station, indicating a transpose of the matrix, ^^argmax, , Sa „*}}, where ^ is the predetermined codebook The codeword, a two-dimensional matrix of N _t xm, represents the conjugate of the matrix ^, abs(HRW;) represents the modulo operation of each element in the matrix f}RW: trace{abs{HRW')} represents the matrix Trace of abs(HRW'), array /^ * of Frobe

尼乌斯范数，为所述等效矩阵。 The Nius norm is the equivalent matrix.

根据本发明的另一个实施例，提供了一种在无线通信网络的基站括以下步骤：接收来自所述用户终端的从所述基站至所述用户终端的下行信道传输矩阵的一个近似等效矩阵的相关信息；基于所述近似等效矩阵的相关信息、预定码书和所述基站中多个发送天线的空间相关矩阵来确定所述近似等效矩阵；利用所述近似等效矩阵对待发送至所述用户终端的下行数据进行预编码。 According to another embodiment of the present invention, there is provided a base station in a wireless communication network comprising the steps of: receiving from the base station to the user terminal from the base station Correlating information about an approximate equivalent matrix of the downlink channel transmission matrix; determining the approximate equivalent matrix based on the correlation information of the approximate equivalent matrix, a predetermined codebook, and a spatial correlation matrix of a plurality of transmitting antennas in the base station; The downlink data to be transmitted to the user terminal is precoded using the approximate equivalent matrix.

在一个实施例中，近似等效矩阵的相关信息包括预定码书中的码字的下标，基站根据 = f ?来确定近似等效矩阵，其中，为所述基站中多个发送天线的空间相关矩阵， k为所述用户终端反馈的预定码书中的码字的下标，为所述预定码书中的码字。 In one embodiment, the correlation information of the approximate equivalent matrix includes a subscript of the codeword in the predetermined codebook, and the base station determines an approximate equivalent matrix according to =f?, where is a space of multiple transmit antennas in the base station a correlation matrix, where k is a subscript of a codeword in a predetermined codebook fed back by the user terminal, and is a codeword in the predetermined codebook.

在一个实施例中，基站对近似等效矩阵进行奇异值分解，然后取奇异值分解后的右侧酉奇异矩阵的前 m 列向量作为预编码矩阵对待发送至所述用户终端的下行数据进行预编码，其中 m 为下行数据流数。 In an embodiment, the base station performs singular value decomposition on the approximate equivalent matrix, and then takes the pre-m column vector of the singular value-decomposed right 酉 singular matrix as a precoding matrix to preprocess the downlink data to be sent to the user terminal. Encoding, where m is the number of downstream streams.

根据本发明的另一个实施例，提供了一种在无线通信网络的用户终端中用于向基站反馈下行信道信息的反馈装置，包括：获取装置，用于获取所述基站至所述用户终端之间的下行信道传输矩阵；第一确定装置，用于根据所述下行信道传输矩阵、下行数据流数、所述基站中多个发送天线的空间相关矩阵和预定码书来确定所述下行信道传输矩阵的一个近似等效矩阵；信息反馈装置，用于将所述近似等效矩阵的相关信息反馈给所述基站。 According to another embodiment of the present invention, a feedback apparatus for feeding back downlink channel information to a base station in a user terminal of a wireless communication network, includes: acquiring means, configured to acquire the base station to the user terminal a downlink channel transmission matrix; the first determining means, configured to determine the downlink channel transmission according to the downlink channel transmission matrix, the number of downlink data streams, a spatial correlation matrix of multiple transmitting antennas in the base station, and a predetermined codebook An approximate equivalent matrix of the matrix; an information feedback device, configured to feed back related information of the approximate equivalent matrix to the base station.

根据本发明的另一个实施例，提供了一种在无线通信网络的基站中用于对待发送至用户终端的下行数据进行预编码的预编码装置，包括：接收装置，用于接收来自所述用户终端的从所述基站至所述用户终端的下行信道传输矩阵的一个近似等效矩阵的相关信息；第四确定装置，用于基于所述近似等效矩阵的相关信息、预定码书和所述基站中多个发送天线的空间相关矩阵来确定所述近似等效矩阵；编码装置，用于利用所述近似等效矩阵对待发送至所述用户终端的下行数据进行预编码。 According to another embodiment of the present invention, there is provided a precoding apparatus for precoding a downlink data to be transmitted to a user terminal in a base station of a wireless communication network, comprising: receiving means for receiving from the user Information about an approximate equivalent matrix of a downlink channel transmission matrix of the terminal from the base station to the user terminal; fourth determining means, configured to, based on the approximate equivalent matrix, related code, a predetermined codebook, and the And determining, by the spatial correlation matrix of the plurality of transmitting antennas in the base station, the approximate equivalent matrix; and encoding means, configured to perform precoding on the downlink data to be sent to the user terminal by using the approximate equivalent matrix.

相比于现有的采用固定码书和暗示反馈的自适应码书进行预编码的无线通信***，采用本发明的技术方案的无线通信***取得明显的增益， ***的误块率（Block Error Rate ) 大为降低。 Compared with the existing wireless communication system for precoding using an adaptive codebook with fixed codebook and implicit feedback, the wireless communication system adopting the technical solution of the present invention achieves obvious The gain, the block error rate of the system is greatly reduced.

在本发明中，由于用户终端向基站反馈了下行信道传输矩阵的一个近似等效矩阵，即明示的反馈，基站根据该近似等效矩阵来确定自主确定预编码方案，因此基站侧可以灵活使用各种预编码方案。另外，根据本发明的一个实施例，预定码书釆用现有的 LTE版本 8中的定义的码书，保持了很好的向后兼容性，计算复杂度较低，使得***的实现更为简单。附图说明 In the present invention, since the user terminal feeds back to the base station an approximate equivalent matrix of the downlink channel transmission matrix, that is, the explicit feedback, the base station determines the autonomously determined precoding scheme according to the approximate equivalent matrix, so the base station side can flexibly use each Kind of precoding scheme. In addition, according to an embodiment of the present invention, the predetermined codebook uses the codebook defined in the existing LTE version 8, which maintains good backward compatibility and low computational complexity, so that the system is more implemented. simple. DRAWINGS

通过阅读以下参照附图对非限制性实施例所作的详细描述，本发明的其它特征、目的和优点将会变得更明显。 Other features, objects, and advantages of the invention will become apparent from the Detailed Description of Description

图 1为根据本发明的一个具体实施方式的无线通信网络的应用场景图示意图； 1 is a schematic diagram of an application scenario of a wireless communication network in accordance with an embodiment of the present invention;

图 2为根据本发明的一个具体实施方式的在无线通信网络的用户终端中用于向基站反馈下行信道信息的方法流程图； 2 is a flow chart of a method for feeding back downlink channel information to a base station in a user terminal of a wireless communication network according to an embodiment of the present invention;

图 3为根据本发明的一个具体实施方式的图 2中所示的步驟 S22 的子步骤流程图； Figure 3 is a flow chart showing the sub-steps of step S22 shown in Figure 2 in accordance with an embodiment of the present invention;

图 4为根据本发明的一个具体实施方式的图 3 中所示步骤 S221 的子步骤流程图； 4 is a flow chart showing the sub-steps of step S221 shown in FIG. 3 according to an embodiment of the present invention;

图 5为根据本发明的另一个具体实施方式的图 3中所示步骤 S221 的子步骤流程图； FIG. 5 is a flow chart showing the sub-steps of step S221 shown in FIG. 3 according to another embodiment of the present invention;

图 6为根据本发明的一个具体实施方式的在无线通信网络的基站图 7为根据本发明的一个具体实施方式的图 6中所示步骤 S63的子步骤流程图； 6 is a base station in a wireless communication network in accordance with an embodiment of the present invention. FIG. 7 is a flowchart of a sub-step of step S63 shown in FIG. 6 in accordance with an embodiment of the present invention;

图 8为根据本发明的一个具体实施方式的在无线通信网络的用户终端中用于向基站反馈下行信道信息的反馈装置的结构框图； 8 is a structural block diagram of a feedback apparatus for feeding back downlink channel information to a base station in a user terminal of a wireless communication network according to an embodiment of the present invention;

图 9为根据本发明的一个具体实施方式的在无线通信网络的基站中用于对待发送至用户终端的下行数据进行预编码的预编码装置的结构框图； 9 is a precoding apparatus for precoding a downlink data to be transmitted to a user terminal in a base station of a wireless communication network according to an embodiment of the present invention. Structure diagram;

图 10表示采取 ITU-UMi信道模型，基站发送天线间距为 0.5倍波长，移动速度为 3Km/h，用户终端具有 2个发送天线，码率为 1/2, 采取 QPSK调制，发送数据流为 1 的无线通信***的误块率与信噪比的示意图； Figure 10 shows the adoption of the ITU-UMi channel model. The base station transmits antennas with a spacing of 0.5 times and a moving speed of 3 Km/h. The user terminal has two transmitting antennas with a code rate of 1/2. QPSK modulation is used, and the transmitted data stream is 1. Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system;

图 11表示采取 ITU-UMi信道模型，基站发送天线间距为 4倍波长，移动速度为 3Km/h, 用户终端具有 2个发送天线，码率为 1/2，采取 QPSK调制，发送数据流为 1的无线通信***的误块率与信噪比的示意图； Figure 11 shows the ITU-UMi channel model. The base station transmits antennas with a 4x wavelength and a moving speed of 3Km/h. The user terminal has two transmit antennas with a code rate of 1/2. QPSK modulation is used and the transmit data stream is 1 Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system;

图 12表示釆取 ITU-UMi信道模型，基站发送天线间距为 0.5波长，移动速度为 3Km/h，用户终端具有 2个发送天线，码率为 1/2, 采取 QPSK调制，发送数据流为 2的无线通信***的误块率与信噪比的示意图； Figure 12 shows the ITU-UMi channel model. The base station transmit antenna spacing is 0.5 wavelength, the moving speed is 3Km/h, the user terminal has 2 transmit antennas, the code rate is 1/2, QPSK modulation is adopted, and the transmit data stream is 2 Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system;

图 13表示采取 ITU-UMa信道模型，基站发送天线间距为 0.5倍波长，移动速度为 3Km/h, 用户终端具有 2个发送天线，码率为 1/2, 采取 QPSK调制，发送数据流为 2的无线通信***的误块率与信噪比的示意图； Figure 13 shows the adoption of the ITU-UMa channel model. The base station transmits antennas with a spacing of 0.5 times and a moving speed of 3 Km/h. The user terminal has two transmitting antennas with a code rate of 1/2. QPSK modulation is used and the transmitted data stream is 2 Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system;

图 14表示采取 ITU-UMi信道模型，基站发送天线间距为 4倍波长，移动速度为 3Km/h，用户终端具有 2个发送天线，码率为 1/2，采取 QPSK调制，发送数据流为 2的无线通信***的误块率与信噪比的示意图； Figure 14 shows the ITU-UMi channel model. The base station transmits antennas with a 4x wavelength and a moving speed of 3Km/h. The user terminal has two transmit antennas with a code rate of 1/2. QPSK modulation is used and the transmit data stream is 2 Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system;

图 15表示采取 ITU-UMa信道模型，基站发送天线间距为 4倍波长，移动速度为 3Km/h，用户终端具有 2个发送天线，码率为 1/2, 采取 QPSK调制，发送数据流为 2的无线通信***的误块率与信噪比的示意图； Figure 15 shows the ITU-UMa channel model. The base station transmits antennas with a 4x wavelength and a moving speed of 3Km/h. The user terminal has two transmit antennas with a code rate of 1/2. QPSK modulation is used and the transmit data stream is 2 Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system;

图 16表示采取 ITU-UMi信道模型，基站发送天线间距为 0.5倍波长，移动速度为 3Km/h，用户终端具有 3个发送天线，码率为 1/2，采取 QPSK调制，发送数据流为 3的无线通信***的误块率与信噪比的示意图；图 17表示釆取 ITU-UMa信道模型，基站发送天线间距为 0.5倍波长，移动速度为 30Km/h,用户终端具有 3个发送天线，码率为 1/2，采取 QPSK调制，发送数据流为 3的无线通信***的误块率与信噪比的示意图； Figure 16 shows the adoption of the ITU-UMi channel model. The base station transmit antenna spacing is 0.5 times the wavelength, the moving speed is 3Km/h, the user terminal has 3 transmit antennas, the code rate is 1/2, QPSK modulation is adopted, and the transmit data stream is 3 Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system; Figure 17 shows the ITU-UMa channel model. The base station transmits antennas with a wavelength of 0.5 times and a moving speed of 30 Km/h. The user terminal has three transmit antennas with a code rate of 1/2. QPSK modulation is used and the data stream is transmitted. 3 is a schematic diagram of a block error rate and a signal to noise ratio of a wireless communication system;

图 18表示采取 ITU-UMi信道模型，基站发送天线间距为 0.5倍波长，移动速度为 3Km/h，用户终端具有 4个发送天线，码率为 1/2, 采取 QPSK调制，发送数据流为 4的无线通信***的误块率与信噪比的示意图； Figure 18 shows the adoption of the ITU-UMi channel model. The base station transmit antenna spacing is 0.5 times the wavelength, the moving speed is 3Km/h, the user terminal has 4 transmit antennas, the code rate is 1/2, QPSK modulation is adopted, and the transmit data stream is 4 Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system;

图 19表示采取 ITU-UMa信道模型，基站发送天线间距为 4倍波长，移动速度为 30Km/h，用户终端具有 4个发送天线，码率为 1/2，采取 QPSK调制，发送数据流为 4的无线通信***的误块率与信噪比的示意图； Figure 19 shows the ITU-UMa channel model. The base station transmits antennas with a 4x wavelength and a moving speed of 30Km/h. The user terminal has 4 transmit antennas with a code rate of 1/2. QPSK modulation is used and the transmit data stream is 4 Schematic diagram of the block error rate and signal to noise ratio of a wireless communication system;

其中，相同或相似的附图标记表示相同或相似的步骤特征或装置 (模块）。具体实施方式 Wherein, the same or similar reference numerals denote the same or similar step features or devices (modules). detailed description

以下结合附图对本发明的具体实施例进行详细的示例性描述。图 1示出了根据本发明的一个具体实施方式的无线通信网络的应用场景图，其中，基站 21 中具有 N_t个发送天线， N_t大于 1 ; 用户终端 11 中具有 N_r个发送天线， N_r大于等于 1。用户终端 11和基站 21 之间的上下行信道为非对称信道，基站 21需要基于用户终端 11反馈的下行信道信息对待发送至用户终端 11 的数据进行预编码后发送给用户终端 11。 The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. 1 shows an application scenario diagram of a wireless communication network according to an embodiment of the present invention, wherein the base station 21 has N _t transmit antennas, N _{t is} greater than 1; the user terminal 11 has N _r transmit antennas, N _{r is} greater than or equal to 1. The uplink and downlink channels between the user terminal 11 and the base station 21 are asymmetric channels, and the base station 21 needs to precode the data to be transmitted to the user terminal 11 based on the downlink channel information fed back by the user terminal 11, and then transmit the data to the user terminal 11.

图 2示出了根据本发明的一个具体实施方式的在无线通信网络的用户终端中用于向基站反馈下行信道信息的方法流程图。以下结合图 1所示的应用场景，对图 2中流程进行详细说明。 2 shows a flow chart of a method for feeding back downlink channel information to a base station in a user terminal of a wireless communication network in accordance with an embodiment of the present invention. The flow in FIG. 2 will be described in detail below with reference to the application scenario shown in FIG. 1.

首先，在步骤 S21 中，用户终端 11获取基站 21至其之间的下行信道传输矩阵 H, H为一个 N N_t的二维矩阵。通常，用户终端 11 可根据其接收到的来自基站 21 的下行信号来进行信道估计以获得下行信道传输矩阵，具体地，如何进行信道估计已是本领域非常成熟的技术，可参阅 John G Proakis所著的《Digital Communications》，在此不再赘述。 First, in step S21, the user terminal 11 acquires the downlink channel transmission matrix H between the base stations 21 and H, which is a two-dimensional matrix of NN _t . Generally, the user terminal 11 can perform channel estimation according to the downlink signal it receives from the base station 21 to obtain the next The line channel transmission matrix, specifically, how to perform channel estimation is a very mature technology in the field, and can be referred to "Digital Communications" by John G Proakis, and will not be described here.

接着，在步骤 S22中，用户终端 11根据基站 21至其的下行信道传输矩阵、下行数据流数 m、基站 21 中多个发送天线的空间相关矩阵 R和预定码书来确定下行信道传输矩阵 H的一个近似等效矩阵^。 Next, in step S22, the user terminal 11 determines the downlink channel transmission matrix H according to the downlink channel transmission matrix to the base station 21, the number of downlink data streams m, the spatial correlation matrix R of the plurality of transmitting antennas in the base station 21, and the predetermined codebook. An approximate equivalent matrix ^.

下行数据流数指基站在一个传输符号的周期内预编码所针对的数据符号的个数，这有可能是无线通信***事先配置好的，也有可能是基站根据实时信道条件来动态地确定。 The number of downlink data streams refers to the number of data symbols for which the base station precodes in a period of one transmission symbol. This may be configured in advance by the wireless communication system, or it may be dynamically determined by the base station according to real-time channel conditions.

在一个实施例中，用户终端 11根据基站 21至其之间的下行信道传输矩阵 H来确定空间相关矩阵，即 R=E[H^H H] , R可以是 Η^ΗΉ在多个时间点和 /或多个子载波上的平均值。在另一个实施例中，用户终端 11也可从基站 21处获取直接获取基站 21 中多个发送天线的空间相关矩阵。基站 21 中多个发送天线的空间相关矩阵 R是一个随时间緩慢变化的物理量，因此，用户终端 11 可以较长时间周期，例如 100ms, 来更新空间相关矩阵 R。 In one embodiment, the user terminal 11 determines a spatial correlation matrix according to the downlink channel transmission matrix H between the base station 21, ie, R=E[H ^H H] , and R may be ^Η Ή at multiple time points and / or average on multiple subcarriers. In another embodiment, the user terminal 11 may also acquire, from the base station 21, a spatial correlation matrix that directly acquires a plurality of transmit antennas in the base station 21. The spatial correlation matrix R of the plurality of transmitting antennas in the base station 21 is a physical quantity that changes slowly with time, and therefore, the user terminal 11 can update the spatial correlation matrix R for a long period of time, for example, 100 ms.

在一个实施例中，步骤 S22 包括如图 3 所示的子步骤 S221 和 S222。 In one embodiment, step S22 includes sub-steps S221 and S222 as shown in FIG.

首先，在步骤 S221中，用户终端 11根据下行信道传输矩阵 H和下行数据流数 m来确定下行信道传输矩阵的一个等效矩阵， ίί为 m x N_t的二维矩阵。 First, in step S221, the user terminal 11 determines an equivalent matrix of the downlink channel transmission matrix according to the downlink channel transmission matrix H and the number of downlink data streams m, where ίί is a two-dimensional matrix of mx N _t .

根据本发明的一个实施例，步骤 S221 包括如图 4所示的两个子步骤 S22111和 S22112。 According to an embodiment of the present invention, step S221 includes two sub-steps S22111 and S22112 as shown in FIG.

首先，在步骤 S22111 中，用户终端 11对基站 21至其的下行信道传输矩阵 H进行奇异值分解： H = u∑v^H。 First, in step S22111, the user terminal 11 performs singular value decomposition on the downlink channel transmission matrix H to which the base station 21 is: H = u ∑ v ^H .

接着，在步骤 S22112中，用户终端 11取奇异值分解得到的右侧酉阵 V的共轭转置矩阵 V^H的前 m行向量作为等效矩阵，即 Next, in step S22112, the user terminal 11 takes the pre-m row vector of the conjugate transposed matrix V ^H of the right 酉 matrix V obtained by the singular value decomposition as an equivalent matrix, that is,

Η ( 1 )

居本发明的另一个实施例，步骤 S221 包括如图 5所示的两个子步骤 S22121和 S22122o Η ( 1 )

In another embodiment of the present invention, step S221 includes two sub-steps S22121 and S22122o as shown in FIG.

这里，步骤 S22121同步骤 S22111, 用户终端 11对基站 21至其的下行信道传输矩阵 H进行奇异值分解： H = u∑v^H。 Here, in step S22121, in step S22111, the user terminal 11 performs singular value decomposition on the downlink channel transmission matrix H to which the base station 21 is: H = u ∑ v ^H .

接着，在步骤 S22122中，用户终端 11取奇异值分解得到的右侧酉奇异矩阵 V的共轭转置矩阵 V^H的前 m行向量与对角矩阵∑的前 m 列且前 m x m个元素组成的对角矩阵∑„，的乘积作为等效矩阵，即 (2)

Next, in step S22122, the user terminal 11 takes the pre-m row vector of the conjugate transpose matrix V ^H of the right-hand singular matrix V obtained by the singular value decomposition and the first m column of the diagonal matrix 且 and the first mxm elements. The product of the diagonal matrix ∑„, as the equivalent matrix, ie (2)

回到图 3, 在步骤 S222中，用户终端 11根据在步骤 S221 中获得的下行信道传输矩阵的等效矩阵 #，下行数据流数 m, 基站 21 中多个发送天线的空间相关矩阵 R和预定码书来确定下行信道传输矩阵的近似等效矩阵 ^。 Returning to Fig. 3, in step S222, the user terminal 11 according to the equivalent matrix # of the downlink channel transmission matrix obtained in step S221, the number of downlink data streams m, the spatial correlation matrix R of the plurality of transmitting antennas in the base station 21, and the predetermined The codebook determines the approximate equivalent matrix ^ of the downlink channel transmission matrix.

根据本发明的一个实施例，预定码书采取 LTE版本 8 ( Release 8 ) 中定义反馈码书，即 PMI码书，根据以下公式来确定下行信道传输矩阵的近似等效矩阵 According to an embodiment of the present invention, the predetermined codebook adopts a feedback codebook defined in LTE Release 8 (Release 8), that is, a PMI codebook, and determines an approximate equivalent matrix of the downlink channel transmission matrix according to the following formula.

H^WjR (3) 其中，为所述基站中多个发送天线的空间相关矩阵， ^表示矩阵的转置，其中，根据如下公式确定： H^WjR (3) where is a spatial correlation matrix of a plurality of transmitting antennas in the base station, and ^ represents a transposition of the matrix, wherein, according to the following formula:

trace{abs{HRW')} Trace{abs{HRW')}

W_k = arg max (4) 其中， ^为所述预定码书中的码字，为 N_txm的二维矩阵，表示矩阵 ^的共轭，《M^? )表示对矩阵^ 中的各个元素进行取模操作， trace{abs{HRW*)}表示矩阵 abs(HRW')的迹，表示矩阵 RW*的弗罗贝尼乌斯范数（）， #为步骤 S221 中获取的等效矩阵，如公式（ 1 ) 或公式（2) 所示。 W _k = arg max (4) where ^ is the codeword in the predetermined codebook, a two-dimensional matrix of N _t xm, representing the conjugate of the matrix ^, and "M^?" representing each of the matrix ^ The element performs a modulo operation, trace{abs{HRW*)} represents the trace of the matrix abs(HRW'), represents the Frobenius norm of the matrix RW* ( ), # is the equivalent matrix obtained in step S221 , as shown in equation (1) or formula (2).

公式（4) 的含义是码字 ^即为预定码书中使得^ ^^(^ )^}取 The meaning of formula (4) is that the code word ^ is the predetermined code book so that ^ ^^(^ ) ^}

RW, 值最大的那个码字。 RW, The codeword with the largest value.

回到图 2，在步骤 S203 中，用户终端 11在步骤步骤 S202中确定的近似等效矩阵的相关信息反馈给基站 21。 Returning to Fig. 2, in step S203, the information about the approximate equivalent matrix determined by the user terminal 11 in step S202 is fed back to the base station 21.

如公式（3 )所示，在上述实施例中，基站 21知晓其多个发送天线的空间相关矩阵 R，并且也预存了上述预定码书，用户终端 11 仅需将将码字 ^的下标 k反馈给基站 21 即可，也即近似等效矩阵的相关信息即为码字 _t的下标 k。 As shown in the formula (3), in the above embodiment, the base station 21 knows the spatial correlation matrix R of its plurality of transmitting antennas, and also prestores the predetermined codebook, and the user terminal 11 only needs to subscript the codeword ^ k is fed back to the base station 21, that is, the relevant information of the approximate equivalent matrix is the subscript k of the codeword _t .

需要说明的是，预定码书不限于上文所述的 LTE版本 8中定义的 PMI码书，其它类型的码书也可以应用于本发明，例如 IEEE802.16m 标准中定义的码书。 It should be noted that the predetermined codebook is not limited to the PMI codebook defined in the LTE Release 8 described above, and other types of codebooks may also be applied to the present invention, such as the codebook defined in the IEEE802.16m standard.

本领域的普通技术人员应能理解，根据所采取的确定基站 21 至用户终端 11 之间的下行信道传输矩阵的近似等效矩阵的具体方式不同，近似等效矩阵的相关信息的所包含的具体信息也有所不同。在一个实施例中，反馈近似等效矩阵的相关信息的一个原则是：使反馈所使用的比特开销最小。 It should be understood by those skilled in the art that, depending on the specific manner of determining the approximate equivalent matrix of the downlink channel transmission matrix between the base station 21 and the user terminal 11, the specific content of the relevant information of the approximate equivalent matrix is included. The information is also different. In one embodiment, one principle for feeding back information about an equivalent matrix is to: minimize the bit overhead used for feedback.

图 6示出了根据本发明的一个具体实施方式的在无线通信网络的基站中用于对待发送至用户终端的下行数据进行预编码的方法流程图。以下结合合图 1所示的应用场景，对图 6中流程进行详细说明。 6 is a flow chart showing a method for precoding downlink data to be transmitted to a user terminal in a base station of a wireless communication network in accordance with an embodiment of the present invention. The flow in Figure 6 will be described in detail below in conjunction with the application scenario shown in Figure 1.

首先，在步骤 S61 中，基站 21接收来自用户终端 11的从基站 21 至用户终端 11的下行信道传输矩阵的一个近似等效矩阵的相关信息。如上文公式（3 )和公式（4 )所示的实施例，近似等效矩阵的相关信息包括预定码书中的码字的下标。在一个实施例中，该预定码书采取 LTE版本 8 ( Release 8 ) 中定义的反馈码书，即 PMI码书。 First, in step S61, the base station 21 receives information on an approximate equivalent matrix of the downlink channel transmission matrix from the base station 21 to the user terminal 11 of the user terminal 11. In the embodiment shown by the formulas (3) and (4) above, the correlation information of the approximate equivalent matrix includes the subscript of the codeword in the predetermined codebook. In one embodiment, the predetermined codebook adopts a feedback codebook defined in LTE Release 8 (Release 8), i.e., a PMI codebook.

接着，在步骤 S62中，基站 21基于步骤 S61 中接收到的近似等效矩阵的相关信息、预定码书和基站 21 中多个发送天线的空间相关矩阵来确定近似等效矩阵。与上文公式（3 )和公式（4 )所示的实施例相对应，基站 21根据公式（3 ) 来确定其至用户终端 11 的下行信道传输矩阵的近似等效矩阵。 Next, in step S62, the base station 21 determines an approximate equivalent matrix based on the correlation information of the approximate equal matrix received in step S61, the predetermined codebook, and the spatial correlation matrix of the plurality of transmitting antennas in the base station 21. Corresponding to the embodiment shown by the above formula (3) and formula (4), the base station 21 determines its approximate equivalent matrix of the downlink channel transmission matrix to the user terminal 11 according to the formula (3).

最后，在步骤 S63中，基站 21利用步骤 S62中获得的近似等效矩阵对待发送至用户终端 11的下行数据进行预编码。 Finally, in step S63, the base station 21 utilizes the approximate equivalent obtained in step S62. The matrix precodes the downlink data sent to the user terminal 11.

在一个实施例中，步骤 S63包括如图 7所示的步骤 S63的两个子步骤 S631和 S632₀ In one embodiment, step S63 includes two sub-steps S631 and S632 ₀ of step S63 as shown in FIG.

首先，在步骤 S631中，基站 21对近似等效矩阵进行奇异值分解得5 = ^∑ 。根据公式（3 ) 和公式（4 ) 所示的实施例，为 m x First, in step S631, the base station 21 performs singular value decomposition on the approximate equivalent matrix to obtain 5 = ^ ∑ . According to the embodiment shown by formula (3) and formula (4), it is m x

N_t的二维矩阵， U_w为 m x m的酉矩阵，∑^为 m x N_t的对角矩阵， v_w"为A two-dimensional matrix of N _t , U _w is a unitary matrix of mxm, ∑^ is a diagonal matrix of mx N _t , v _w "

N_t x N_t的酉矩阵，亦为 N_t x N_t的酉矩阵。 N _{_t} x N _t unitary matrix, also the N _{_t} x N _t unitary matrix.

接着，在步骤 S632中，基站 21取奇异值分解后的右侧酉奇异矩阵^的前 m列向量作为预编码矩阵对待发送至用户终端 11的下行数据进行预编码，也即基站 21中的预编码矩阵 P为： = ... ), 其中，为矩阵中的列向量， ...， m。设下行数据流为 m = Next, in step S632, the base station 21 takes the pre-m column vector of the singular value-decomposed right 酉 singular matrix ^ as a precoding matrix to precode the downlink data to be sent to the user terminal 11, that is, the pre-base station 21 The coding matrix P is: = ... ), where is the column vector in the matrix, ..., m. Let the downstream data stream be m =

则得到各个天线上待发送的信号为 S=P X S 为

Then, the signal to be transmitted on each antenna is obtained as S=PXS.

N_t x 1的矩阵。 A matrix of N _t x 1 .

需要说明的是，图 7中所示的流程仅是一个实施例，由于用户终端 11反馈的是基站 21至其的下行信道传输矩阵的一个等效矩阵而非是预编码的码字指示符，因此，基站 21 可自主确定采取的预编码方案，例如基站 21还可以基于其至用户终端 11的下行信道传输矩阵的近似等效矩阵，采取 MET等方法来对待发送至用户终端 11的下行数据进行预编码。关于 MET预编码的详细信息可参考 LTE-A中讨论的技术文档 Rl -070318 , " Link-level Results for Multiuser Eigenmod Transmission with Limited Feedback"。 It should be noted that the flow shown in FIG. 7 is only one embodiment. Since the user terminal 11 feeds back an equivalent matrix of the downlink channel transmission matrix of the base station 21 to it instead of a precoded codeword indicator, Therefore, the base station 21 can autonomously determine the precoding scheme to be adopted. For example, the base station 21 can also adopt the MET or the like to process the downlink data to be sent to the user terminal 11 based on the approximate equivalent matrix of the downlink channel transmission matrix to the user terminal 11. Precoding. For more information on MET precoding, refer to Technical Document Rl - 070318, "Link-level Results for Multiuser Eigenmod Transmission with Limited Feedback", discussed in LTE-A.

图 8为根据本发明的一个具体实施方式的在无线通信网络的用户终端中用于向基站反馈下行信道信息的反馈装置 80的结构框图。在图 8中，反馈装置 80包括获取装置 81、第一确定装置 82、信息反馈装置 83。在一个实施例中，第一确定装置 82 包括第二确定装置 821和第三确定装置 822。以下结合图 1所示的应用场景，对位于用户终端 11 中的反馈装置 80的工作过程进行详细说明。 FIG. 8 is a structural block diagram of a feedback apparatus 80 for feeding back downlink channel information to a base station in a user terminal of a wireless communication network according to an embodiment of the present invention. In FIG. 8, the feedback device 80 includes an acquisition device 81, a first determination device 82, and an information feedback device 83. In one embodiment, the first determining means 82 comprises a second determining means 821 and a third determining means 822. The working process of the feedback device 80 located in the user terminal 11 will be described in detail below with reference to the application scenario shown in FIG.

首先，获取装置 81获取基站 21至其之间的下行信道传输矩阵 H， H为一个 N_r x N_t的 X二维矩阵。通常，用户终端 11可根据其接收到的来自基站 21的下行信号来进行信道估计以获得下行信道传输矩阵，具体地，如何进行信道估计已是本领域非常成熟的技术，可参阅 John G Proakis所著的《Digit Communications》，在 J>匕不再赘述。 First, the acquisition means 81 acquires the downlink channel transmission matrix H between the base stations 21 and H, which is an X two-dimensional matrix of N _r x N _t . Generally, the user terminal 11 can perform channel estimation according to the downlink signal received from the base station 21 to obtain a downlink channel transmission matrix. Specifically, how to perform channel estimation is a very mature technology in the field, and can be found in John G Proakis. "Digit Communications" will not be repeated in J>.

接着，第一确定装置 82根据基站 21至其的下行信道传输矩阵、下行数据流数 m、基站 21 中多个发送天线的空间相关矩阵 R和预定码书来确定下行信道传输矩阵 H的一个近似等效矩阵^。 Next, the first determining means 82 determines an approximation of the downlink channel transmission matrix H according to the downlink channel transmission matrix to the base station 21, the number of downlink data streams m, the spatial correlation matrix R of the plurality of transmitting antennas in the base station 21, and the predetermined codebook. Equivalent matrix ^.

在一个实施例中，获取装置 81根据基站 21至其之间的下行信道传输矩阵 H来确定空间相关矩阵，即 R=E[H^H'H]，可以是 Η^ΗΉ在多个时间点和 /或多个子载波上的平均值。在另一个实施例中，获取装置 81从基站 21处获取基站 21 中多个发送天线的空间相关矩阵 R。基站 21 中多个发送天线的空间相关矩阵 R是一个随时间緩慢变化的物理量，因此，获取装置 81 可以较长时间周期，例如 100ms, 来更新空间相关矩阵1 。 In an embodiment, the obtaining means 81 determines the spatial correlation matrix according to the downlink channel transmission matrix H between the base station 21, that is, R = E[H ^H 'H], which may be ^Η Ή at multiple time points and / or average on multiple subcarriers. In another embodiment, the acquisition device 81 acquires the spatial correlation matrix R of the plurality of transmit antennas in the base station 21 from the base station 21. The spatial correlation matrix R of the plurality of transmitting antennas in the base station 21 is a physical quantity that changes slowly with time. Therefore, the obtaining means 81 can update the spatial correlation matrix 1 for a long period of time, for example, 100 ms.

在一个实施例中，第一确定装置 82的功能通过其两个子装置第二确定装置 821和第三确定装置 822来实现。 In one embodiment, the functionality of the first determining means 82 is effected by its two sub-devices second determining means 821 and third determining means 822.

首先，第二确定装置 821根据下行信道传输矩阵 H和下行数据流数 m来确定下行信道传输矩阵的一个等效矩阵，为 m x N_t的二维矩阵。 First, the second determining means 821 determines an equivalent matrix of the downlink channel transmission matrix according to the downlink channel transmission matrix H and the number of downlink data streams m, which is a two-dimensional matrix of mx N _t .

根据本发明的一个实施例，第二确定装置 821对基站 21至其的下行信道传输矩阵 H进行奇异值分解： H = U∑V^H。 According to an embodiment of the present invention, the second determining means 821 performs singular value decomposition on the downlink channel transmission matrix H to which the base station 21 is: H = U ∑ V ^H .

接着，第二确定装置 821取奇异值分解得到的右侧酉奇异矩阵 V 的共轭转置矩阵 V^H的前 m行向量作为等效矩阵，即如公式（ 1 )所根据本发明的另一个实施例，第二确定装置 821取奇异值分解得到的右侧酉奇异矩阵 V的共轭转置矩阵 V^H的前 m行向量与对角矩阵 ∑的前 m列且前 m行中的 m X m个元素组成的对角矩阵∑„,的乘积作为等效矩阵 #，即如公式（2 ) 所示。 Next, the second determining means 821 takes the pre-m row vector of the conjugate transposed matrix V ^H of the right-hand singular matrix V obtained by the singular value decomposition as an equivalent matrix, that is, as shown in the formula (1) According to another embodiment of the present invention, the second determining means 821 takes the pre-m row vector of the conjugate transposed matrix V ^H of the right-hand singular matrix V obtained by the singular value decomposition and the front m-column of the diagonal matrix 且 and before The product of the diagonal matrix ∑„, composed of m X m elements in m rows, is taken as the equivalent matrix #, as shown in equation (2).

接着，第三确定装置 822根据获取装置 81获得的下行信道传输矩阵的等效矩阵# , 下行数据流数 m，基站 21 中多个发送天线的空间相关矩阵 R和预定码书来确定下行信道传输矩阵的近似等效矩阵根据本发明的一个实施例，预定码书采取 LTE版本 8 ( Release 8 ) 中定义反馈码书，即 PMI码书，第三确定装置 822根据上文所述公式 ( 3 ) 来确定下行信道传输矩阵的近似等效矩阵 ^。 Next, the third determining means 822 determines the downlink channel transmission according to the equivalent matrix # of the downlink channel transmission matrix obtained by the obtaining means 81, the number of downlink data streams m, the spatial correlation matrix R of the plurality of transmitting antennas in the base station 21, and the predetermined codebook. Approximate Equivalent Matrix of Matrix According to an embodiment of the present invention, the predetermined codebook adopts a feedback codebook defined in LTE Release 8 (Release 8), that is, a PMI codebook, and the third determining means 822 is based on the formula (3) described above. To determine the approximate equivalent matrix ^ of the downlink channel transmission matrix.

最后，信息反馈装置 83将第一确定装置 82确定的近似等效矩阵的相关信息反馈给基站 21。 Finally, the information feedback means 83 feeds back the relevant information of the approximate equivalent matrix determined by the first determining means 82 to the base station 21.

如公式（3 )所示，在上述实施例中，基站 21知晓其多个发送天线的空间相关矩阵 R，并且也预存了上述预定码书，信息反馈装置 83 仅需将将码字的下标 k反馈给基站 21即可，也即近似等效矩阵 ^的相关信息即为码字 W_k的下标 k。 As shown in the formula (3), in the above embodiment, the base station 21 knows the spatial correlation matrix R of its plurality of transmitting antennas, and also prestores the predetermined codebook, and the information feedback device 83 only needs to subscript the codeword. to 21 k to the base station, i.e., approximately equivalent to a matrix-related information is the code word W is ^ _k subscript k.

本领域的普通技术人员应能理解，根据所采取的确定基站 21 至用户终端 11 之间的下行信道传输矩阵的近似等效矩阵的具体方式不同，近似等效矩阵 ^的相关信息的所包含的具体信息也有所不同。在一个实施例中，反馈近似等效矩阵 ^的相关信息的一个原则是：使反馈所使用的比特开销最小。 It should be understood by those skilled in the art that, according to the specific manner of determining the approximate equivalent matrix of the downlink channel transmission matrix between the base station 21 and the user terminal 11, the information about the relevant information of the approximate matrix ^ is included. The specific information is also different. In one embodiment, one principle of feeding back information about the equivalent matrix ^ is: Minimize the bit overhead used for feedback.

图 9示出了根据本发明的一个具体实施方式的在无线通信网络的置 90的结构框图。预编码装置 90 包括接收装置 91、第四确定装置 92和编码装置 93。 Figure 9 is a block diagram showing the structure of a wireless communication network in accordance with an embodiment of the present invention. The precoding device 90 includes a receiving device 91, a fourth determining device 92, and an encoding device 93.

以下结合合图 1所示的应用场景，对位于基站 21 中的预编码装置 90的工作过程进行详细说明。首先，接收装置 91接收来自用户终端 11 的从基站 21至用户终端 11 的下行信道传输矩阵的一个近似等效矩阵的相关信息。如上文公式（3)和公式（4)所示的实施例，近似等效矩阵的相关信息包括预定码书中的码字的下标。在一个实施例中，该预定码书采取 LTE 版本 8 ( Release 8 ) 中定义的反馈码书，即 PMI码书。 The working process of the precoding apparatus 90 located in the base station 21 will be described in detail below in conjunction with the application scenario shown in FIG. First, the receiving device 91 receives related information of an approximate equivalent matrix of the downlink channel transmission matrix from the base station 21 to the user terminal 11 from the user terminal 11. As in the embodiment shown by the formulas (3) and (4) above, the related information of the approximate equivalent matrix includes the subscript of the codeword in the predetermined codebook. In one embodiment, the predetermined codebook adopts a feedback codebook defined in LTE Release 8 (Release 8), ie, a PMI codebook.

接着，第四确定装置 92基于接收装置 91接收到的近似等效矩阵的相关信息、预定码书和基站 21 中多个发送天线的空间相关矩阵来确定近似等效矩阵。与上文公式（3)和公式（4)所示的实施例相对应，基站 21根据公式（3) 来确定其至用户终端 11 的下行信道传输矩阵的近似等效矩阵。 Next, the fourth determining means 92 determines an approximate equivalent matrix based on the correlation information of the approximate equivalent matrix received by the receiving means 91, the predetermined codebook, and the spatial correlation matrix of the plurality of transmitting antennas in the base station 21. Corresponding to the embodiment shown by the above formulas (3) and (4), the base station 21 determines its approximate equivalent matrix of the downlink channel transmission matrix to the user terminal 11 according to the formula (3).

最后，编码装置 93利用第四确定装置 92确定的近似等效矩阵对待发送至用户终端 11的下行数据进行预编码。 Finally, the encoding means 93 precodes the downlink data to be transmitted to the user terminal 11 using the approximate equivalent matrix determined by the fourth determining means 92.

在一个实施例中，编码装置 93的具体工作过程如下文所述。 In one embodiment, the specific operation of encoding device 93 is as follows.

首先，编码装置 93 对近似等效矩阵进行奇异值分解得 u i ¹。根据公式（3) 和公式（4) 所示的实施例，为 mxN_t 的二维矩阵， 1^为 111 111的酉矩阵， ∑„为 mxN_t的对角矩阵， V_W ^H为 N_txN_t的酉矩阵，亦为 N_txN_t的酉矩阵。 First, the encoding device 93 performs singular value decomposition on the approximate equivalent matrix to obtain ui ¹ . According to the embodiment shown by formula (3) and formula (4), it is a two-dimensional matrix of mxN _t , 1^ is a 酉 matrix of 111 111, ∑„ is a diagonal matrix of mxN _t , and V _W ^H is N _t xN The unitary matrix of _t , which is also the unitary matrix of N _t xN _t .

接着，编码装置 93取奇异值分解后的右侧酉奇异矩阵 ^的前 m 列向量作为预编码矩阵对待发送至用户终端 11 的下行数据进行预编码，也即基站 21 中的预编码矩阵 P为： ρ = ( ... ν;) 其中，为矩阵^中的列向量， i=l， ... 则得到各 Next, the encoding device 93 precodes the downlink data of the singular value-decomposed right 酉 singular matrix ^ as the precoding matrix to be transmitted to the user terminal 11, that is, the precoding matrix P in the base station 21 is : ρ = ( ... ν;) where, is the column vector in the matrix ^, i=l, ...

个天线上待发送的信号为 N_tx 1的矩

The signal to be transmitted on the antenna is the moment of N _t x 1

阵。 Array.

需要说明的是，上文所述的编码装置 93 的工作过程仅是示例，由于用户终端 11反馈的是基站 21至其的下行信道传输矩阵的一个等效矩阵而非是预编码的码字指示符，因此，编码装置 93可自主确定采取的预编码方案，例如编码装置 93还可以基于其至用户终端 11的下行信道传输矩阵的近似等效矩阵，采取 MET等方法来对待发送至用户终端 11的下行数据进行预编码。关于 MET预编码的详细信息可参考 LTE-A 中讨论的技术文档 Rl-070318, "Link-level Results for Multiuser Eigenmod Transmission with Limited Feedback"。 It should be noted that the working process of the encoding apparatus 93 described above is only an example, since the user terminal 11 feeds back an equivalent matrix of the downlink channel transmission matrix of the base station 21 to it instead of the precoded codeword indication. Therefore, the encoding device 93 can determine autonomously The precoding scheme employed, for example, the encoding device 93 may also precode the downlink data to be transmitted to the user terminal 11 by means of MET or the like based on its approximate equivalent matrix to the downlink channel transmission matrix of the user terminal 11. For more information on MET precoding, refer to Technical Document Rl-070318, "Link-level Results for Multiuser Eigenmod Transmission with Limited Feedback", discussed in LTE-A.

以上对本发明的各个方法实施例和装置实施例进行了详细说明。以下以单用户 MIMO 无线通信***为例，对采用本发明的自适应码书和明示反馈的技术方案，现有技术的自适应码书和暗示反馈的技术方案、固定码书和明示反馈的技术方案、以及固定码书和暗示反馈的技术方案、基于理想信道信息进行 SVD分解的技术方案的性能进行比较分析。 The various method embodiments and device embodiments of the present invention have been described in detail above. The following takes a single-user MIMO wireless communication system as an example, and adopts the technical scheme of the adaptive codebook and explicit feedback of the present invention, the prior art technical scheme of adaptive codebook and suggestive feedback, fixed codebook and explicit feedback technology. The scheme, as well as the technical scheme of fixed codebook and suggestive feedback, and the performance of the technical scheme of SVD decomposition based on ideal channel information are compared and analyzed.

不失一般性的，设基站 21具有四个发送天线，用户终端 11中具有 2到 4个发送天线，预定码书采用 LTE版本 8中定义的反馈码书，即 PMI码书，仿真信道釆用 ITU信道模型，详细的仿真参数如下表所示。 Without loss of generality, the base station 21 has four transmit antennas, and the user terminal 11 has two to four transmit antennas. The predetermined codebook uses a feedback codebook defined in LTE Release 8, that is, a PMI codebook, and the simulation channel is used. The ITU channel model, detailed simulation parameters are shown in the table below.

表 1 仿真参数表 Table 1 Simulation parameter table

参数名称取值 Parameter name

传输方案一至四阶的 SVD SU-MIMO Transmission scheme SVD SU-MIMO from first to fourth order

基站数目和天线配置一个基站，具有四个天线，天线间距为 0.5 倍波长或者 4倍波长 Number of base stations and antenna configuration One base station with four antennas with an antenna spacing of 0.5 times or 4 times

用户终端数目和天线一个用户终端，具有二至四个天线，天线间配置距为 0.5倍波长 Number of user terminals and antennas One user terminal, with two to four antennas, with an inter-antenna configuration spacing of 0.5 times the wavelength

调制方案 QPSK Modulation scheme QPSK

信道编码 1/2 Turbo 编码 Channel coding 1/2 Turbo coding

信道状态信息（CSI ) 0 ms Channel Status Information (CSI) 0 ms

反馈延时 Feedback delay

发射机相关矩阵报告 0 ms Transmitter correlation matrix report 0 ms

延时 Delay

发射机相关矩阵量化理想 ( Ideal ) 方案 Transmitter correlation matrix quantization ideal ( Ideal ) Program

传输资源频域的 5 LTE PRBs ( Primary Resource Transmission Resources Frequency Domain 5 LTE PRBs ( Primary Resource

Block ) Block )

信道估计理想 ( Ideal ) Channel estimation ideal ( Ideal )

数据检测 MMSE Data detection MMSE

速度 3kmph or 30kmph Speed 3kmph or 30kmph

快速衰落信道模型 ITU信道模型， UMi( Urban Micro )或者 UMa Fast fading channel model ITU channel model, UMi (Urban Micro) or UMa

( Urban Macro ) ( Urban Macro )

大尺度信道模型无损模型 Large scale channel model lossless model

仿真帧数 1000 Number of simulation frames 1000

块大小 584 bits Block size 584 bits

预定码书 3 GPP LTE Rel -8 4 bits codebook for 4Tx 理想的 SVD分解方案的信噪比与误比特率的关系曲线图，其中，横坐标表示信噪比（SNR ), 单位为 dB , 纵坐标表示误块率（BLER ), 单位为百分比；图例实线加圆圏表示本发明的自适应码书和明示反馈的技术方案，图例实线加三角形表示现有技术的自适应码书和暗示反馈的技术方案，图例实线加正方形表示现有技术中的固定码书和明示反馈的技术方案，图例实线加菱形表示现有技术中的固定码书和暗示反馈的技术方案，图例虚线加圆圈表示基于理想信道信息进行 SVD 分解的技术方案。 Predetermined code book 3 GPP LTE Rel -8 4 bits codebook for 4Tx The relationship between the signal-to-noise ratio and the bit error rate of the ideal SVD decomposition scheme, where the abscissa represents the signal-to-noise ratio (SNR), the unit is dB, and the ordinate Indicates the block error rate (BLER), the unit is percentage; the legend solid line plus circle 圏 represents the technical scheme of the adaptive codebook and explicit feedback of the present invention, and the legend solid line plus triangle represents the prior art adaptive codebook and implied feedback. The technical solution, the solid line plus the legend represents the technical solution of the fixed codebook and the explicit feedback in the prior art, and the solid line plus the diamond in the legend represents the technical solution of the fixed codebook and the hint feedback in the prior art, and the dotted line is circled. A technical solution for performing SVD decomposition based on ideal channel information.

表 2示出了当误块率为 0.1为各个技术方案的信噪比。 Table 2 shows the signal-to-noise ratio for each technical solution when the block error rate is 0.1.

表 2 误块率为 0.1的信噪比 Table 2 Signal to noise ratio with a block error rate of 0.1

自适应码书自适应码书固定码书固定码书 ***参数 Adaptive codebook adaptive codebook fixed codebook fixed codebook system parameters

明示反馈暗示反馈明示反馈暗示反馈发送数据流为 1， Explicit feedback implied feedback explicit feedback implied feedback sent data stream is 1,

UMi 信道模型，发 UMi channel model, hair

-3.2 dB -3.2 dB -2.4 dB -2.4 dB 送天线间距 0.5 倍 -3.2 dB -3.2 dB -2.4 dB -2.4 dB Transmitting antenna spacing 0.5 times

波长发送数据流为 1， Wavelength The send data stream is 1,

UMi 信道模型，发 UMi channel model, hair

-3.4 dB -3.4 dB -3 dB -3 dB 送天线间距 4倍波 -3.4 dB -3.4 dB -3 dB -3 dB Transmitting antenna spacing 4 times wave

长 Long

发送数据流为 2， Send the data stream to 2,

UMi 信道模型，发 UMi channel model, hair

5.4 dB 12 dB 6.2 dB 6.2 dB 送天线间距 0.5 倍 5.4 dB 12 dB 6.2 dB 6.2 dB Transmitting antenna spacing 0.5 times

波长 Wavelength

发送数据流为 2， Send the data stream to 2,

UMa信道模型，发 UMa channel model, hair

5.5 dB 11 dB 6.4 dB 6.4 dB 送天线间距 0.5 倍 5.5 dB 11 dB 6.4 dB 6.4 dB Transmitting antenna spacing 0.5 times

波长 Wavelength

发送数据流为 2， Send the data stream to 2,

UMi 信道模型，发 UMi channel model, hair

4 dB 6.8 dB 4.5 dB 4.6 dB 送天线间巨 4倍波 4 dB 6.8 dB 4.5 dB 4.6 dB Send antenna between antennas 4 times

长 Long

发送数据流为 2， Send the data stream to 2,

UMa信道模型，发 UMa channel model, hair

4.4 dB 7.8 dB 5.2 dB 5.3 dB 送天线间距 4倍波 4.4 dB 7.8 dB 5.2 dB 5.3 dB Transmitting antenna spacing 4 times wave

长 Long

发送数据流为 3, Send the data stream to 3,

UMi 信道模型，发 UMi channel model, hair

8.5 dB 大于 12 dB 10 dB 10 dB 送天线间巨 0.5 倍 8.5 dB greater than 12 dB 10 dB 10 dB 0.5 times larger between antennas

波长 Wavelength

发送数据流为 3， Send the data stream to 3,

UMa信道模型，发 UMa channel model, hair

8.8 dB 大于 12 dB 10.3 dB 10.3 dB 送天线间距 0.5 倍 8.8 dB greater than 12 dB 10.3 dB 10.3 dB Transmitting antenna spacing 0.5 times

波长 Wavelength

发送数据流为 4， 13.5 dB 大于 18 dB 14.2 dB 14 dB UMi 信道模型，发 Transmit data stream is 4, 13.5 dB greater than 18 dB 14.2 dB 14 dB UMi channel model, hair

送天线间巨 0.5 倍 Send antennas hugely 0.5 times

波长 Wavelength

发送数据流为 4, Send the data stream to 4,

UMa信道模型，发 UMa channel model, hair

14 dB 大于 18 dB 14.5 dB 14.4 dB 送天线间距 0.5 倍 14 dB greater than 18 dB 14.5 dB 14.4 dB Transmitting antenna spacing 0.5 times

波长 Wavelength

由图 10至图 19可以看出，与现有技术中的方案相比，本发明的自适应码书和明示反馈的技术方案在同样的信噪比的情形下，误块率最低，或者在同样误块率的情形下，信噪比最低。 As can be seen from FIG. 10 to FIG. 19, compared with the prior art solution, the technical solution of the adaptive codebook and the explicit feedback of the present invention has the lowest block error rate in the case of the same signal-to-noise ratio, or In the case of the same block error rate, the signal-to-noise ratio is the lowest.

需要说明的是，上述实施例仅是示范性的，而非对本发明的限制。任何不背离本发明精神的技术方案均应落入本发明的保护范围之内。此夕卜，不应将权利要求中的任何附图标记视为限制所涉及的权利要求； "包括"一词不排除其它权利要求或说明书中未列出的装置或步骤；装置前的 "一个" 不排除多个这样的装置的存在；在包含多个装置的设备中，该多个装置中的一个或多个的功能可由同一个硬件或软件模块来实现； "第一"、 "第二"、 "第三" 等词语仅用来表示名称，而并不表示任何特定的顺序。 It should be noted that the above embodiments are merely exemplary and not limiting of the invention. Any technical solution that does not depart from the spirit of the present invention should fall within the scope of the present invention. In addition, any reference signs in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the means or steps that are not listed in the other claims or the description; "The existence of a plurality of such devices is not excluded; in a device comprising a plurality of devices, the functionality of one or more of the plurality of devices may be implemented by the same hardware or software module; "first", "second Words such as ", "third" are used only to denote names, and do not denote any particular order.

Claims

权利要求书 Claim

1. 一种在无线通信网络的用户终端中用于向基站反馈下行信道信息的方法，其中，包括以下步骤： A method for feeding back downlink channel information to a base station in a user terminal of a wireless communication network, comprising the following steps:

A. 获取所述基站至所述用户终端之间的下行信道传输矩阵； A. acquiring a downlink channel transmission matrix between the base station and the user terminal;

B. 根据所述下行信道传输矩阵、下行数据流数、所述基站中多个发送天线的空间相关矩阵和预定码书来确定所述下行信道传输矩阵的一个近似等效矩阵； B. determining an approximate equivalent matrix of the downlink channel transmission matrix according to the downlink channel transmission matrix, the number of downlink data streams, a spatial correlation matrix of a plurality of transmitting antennas in the base station, and a predetermined codebook;

C. 将所述近似等效矩阵的相关信息反馈给所述基站。 C. Feed back related information of the approximate equivalent matrix to the base station.

2. 根据权利要求 1 所述的方法，其中，在所述步骤 B之前还包括以下步骤： 2. The method according to claim 1, wherein before the step B, the method further comprises the following steps:

- 获取所述基站中多个发送天线的空间相关矩阵。 - acquiring a spatial correlation matrix of a plurality of transmit antennas in the base station.

3. 根据权利要求 1所述的方法，其中，所述下行数据流数为 m, 所述基站中具有 N_t个发送天线，所述步骤 B包括以下步骤： The method of claim 1, wherein the number of downlink data flows is m, the base station has N _t transmit antennas, and the step B includes the following steps:

B1. 根据所述下行信道传输矩阵和所述下行数据流数来确定所述下行信道传输矩阵的一个等效矩阵，该等效矩阵为 m x N_t的二维矩阵； B1. determining, according to the downlink channel transmission matrix and the number of downlink data streams, an equivalent matrix of the downlink channel transmission matrix, where the equivalent matrix is a two-dimensional matrix of mx N _t ;

B2. 根据所述等效矩阵、所述下行数据流数、所述空间相关矩阵和所述预定码书来确定所述近似等效矩阵，所述近似等效矩阵为 m x N_t的二维矩阵。 B2. determining the approximate equivalent matrix according to the equivalent matrix, the number of downlink data streams, the spatial correlation matrix, and the predetermined codebook, where the approximate equivalent matrix is a two-dimensional matrix of mx N _t .

4. 根据权利要求 3所述的方法，其中，所述步骤 B1包括以下步骤： 4. The method according to claim 3, wherein the step B1 comprises the following steps:

Bi l l . 对所述下行信道传输矩阵 H进行奇异值分解得 H = U∑v^H； B112. 取所述奇异值分解得到的右侧酉奇异 V 的共轭转置

Bi ll. Perform singular value decomposition on the downlink channel transmission matrix H to obtain H = U ∑ v ^H ; B112. Take the conjugate input of the singular value decomposition to obtain the conjugate transpose of the right singular singular V

矩阵 V^H的前 m行向量作为所述等效矩阵， H = The first m row vector of the matrix V ^H is taken as the equivalent matrix, H =

5. 根据权利要求 3所述的方法，其中，所述步骤 B1包括以下步骤： 5. The method according to claim 3, wherein the step B1 comprises the following steps:

B121. 对所述下行信道传输矩阵 H进行奇异值分解得 H = u∑v^H ; B122. 取所述奇异值分解得到右侧酉奇异矩阵 V 的共轭转置矩阵 V^H的前 m行向量与对角矩阵∑的前 m列且前 m行中的 x m个元素组成的对角矩阵∑„的乘积作为所述等效矩阵， H =∑B121. performing singular value decomposition on the downlink channel transmission matrix H to obtain H=u∑v ^H ; B122. Taking the singular value decomposition to obtain a diagonal of the front m-row vector of the conjugate transposed matrix V ^H of the right-hand singular matrix V and the first m-column of the diagonal matrix 且 and the xm elements in the first m-row The product of the matrix ∑„ is taken as the equivalent matrix, H =∑

6.根据权利要求 3所述的方法，其中所述步骤 B2包括以下步骤： - 根据以下公式来确定所述近似等效矩阵^ : The method according to claim 3, wherein said step B2 comprises the step of: - determining said approximate equivalent matrix ^ according to the following formula:

H = W_k ^TR H = W _k ^T R

其中， R为所述基站中多个发送天线的空间相关矩阵， ^表示矩阵的转置， T^ argmax, 其中， ,为所述预定码书中的码字，为 N_t x m的二维矩阵，表示矩阵 ^的共轭， abs(ii勝 Ά 示对矩阵中的各个元素进行取模操作， t_race{« (^ )}表示矩阵 abs^RW:)的迹, |^ ^表示矩阵的弗罗贝尼乌斯范数， #为所述等效矩阵； Where R is a spatial correlation matrix of a plurality of transmit antennas in the base station, ^ represents a transpose of the matrix, T^ argmax, where, is a codeword in the predetermined codebook, a two-dimensional matrix of N _t xm , denotes the conjugate of the matrix ^, abs (ii wins the modulo operation on each element in the matrix, t _rac e{« (^ )} denotes the trace of the matrix abs^RW:), |^ ^ denotes the matrix Frobenius norm, # is the equivalent matrix;

其中，所述近似等效矩阵的相关信息包括所述码字 ^的下标 k , 所述反馈步骤包括以下步骤： The related information of the approximate equivalent matrix includes a subscript k of the codeword ^, and the feedback step includes the following steps:

- 将码字 ^的下标 k反馈给所述基站。 - Feeding the subscript k of the codeword ^ to the base station.

7. 根据权利要求 1 所述的方法，其中，所述预定码书包括 LTE 版本 8中定义的反馈码书。 7. The method according to claim 1, wherein the predetermined codebook comprises a feedback codebook defined in LTE Rel-8.

8. —种在无线通信网络的基站中用于对待发送至用户终端的下行数据进行预编码的方法，其中，包括以下步骤： 8. A method for precoding a downlink data to be transmitted to a user terminal in a base station of a wireless communication network, comprising the steps of:

I. 接收来自所述用户终端的从所述基站至所述用户终端的下行信道传输矩阵的一个近似等效矩阵的相关信息； I. receiving related information of an approximate equivalent matrix of a downlink channel transmission matrix from the base station to the user terminal from the user terminal;

II. 基于所述近似等效矩阵的相关信息、预定码书和所述基站中多个发送天线的空间相关矩阵来确定所述近似等效矩阵； II. determining the approximate equivalent matrix based on correlation information of the approximate equivalent matrix, a predetermined codebook, and a spatial correlation matrix of a plurality of transmit antennas in the base station;

III. 利用所述近似等效矩阵对待发送至所述用户终端的下行数据进行预编码。 III. Precoding the downlink data to be sent to the user terminal using the approximate equivalent matrix.

9. 根据权利要求 8所述的方法，其中，所述近似等效矩阵的相关信息包括所述预定码书中的码字的下标，所述步骤 II 包括以下步 - 根据以下公式来确定所述近似等效矩阵： 9. The method according to claim 8, wherein the related information of the approximate equivalent matrix includes a subscript of a codeword in the predetermined codebook, and the step II includes the following steps - Determine the approximate equivalent matrix according to the following formula:

S = W_k ^rR , 其中， ?为所述基站中多个发送天线的空间相关矩阵，定码书中的码字。 S = W _k ^r R , where ? is a spatial correlation matrix of a plurality of transmitting antennas in the base station, and a codeword in the fixed code book.

10. 根据权利要求 8所述的方法，其中，所述步骤 III包括以下步骤： 10. The method according to claim 8, wherein the step III comprises the following steps:

- 对所述近似等效矩阵进行奇异值分解； - performing singular value decomposition on the approximate equivalent matrix;

- 取奇异值分解后的右侧酉奇异矩阵的前 m 列向量作为预编码 - taking the pre-m column vector of the right 酉 singular matrix after singular value decomposition as precoding

11. 根据权利要求 8所述的方法，其中，所述预定码书包括 LTE 版本 8中定义的反馈码书。 11. The method according to claim 8, wherein the predetermined codebook comprises a feedback codebook defined in LTE Rel-8.

12. 一种在无线通信网络的用户终端中用于向基站反馈下行信道信息的反馈装置，包括： 12. A feedback device for feeding back downlink channel information to a base station in a user terminal of a wireless communication network, comprising:

获取装置，用于获取所述基站至所述用户终端之间的下行信道传输矩阵； And an acquiring device, configured to acquire a downlink channel transmission matrix between the base station and the user terminal;

第一确定装置，用于根据所述下行信道传输矩阵、下行数据流数、所述基站中多个发送天线的空间相关矩阵和预定码书来确定所述下行信道传输矩阵的一个近似等效矩阵； a first determining means, configured to determine an approximate equivalent matrix of the downlink channel transmission matrix according to the downlink channel transmission matrix, the number of downlink data streams, a spatial correlation matrix of multiple transmitting antennas in the base station, and a predetermined codebook ;

信息反馈装置，用于将所述近似等效矩阵的相关信息反馈给所述基站。 And an information feedback device, configured to feed back related information of the approximate equivalent matrix to the base station.

13. 根据权利要求 12所述的反馈装置，其中，所述下行数据流数为 m，所述基站中具有 N_t个发送天线，所述第一确定装置包括：第二确定装置，用于根据所述下行信道传输矩阵和所述下行数据流数来确定所述下行信道传输矩阵的一个等效矩阵，该等效矩阵为 m x N_t的二维矩阵； The feedback device according to claim 12, wherein the number of downlink data streams is m, the base station has N _t transmit antennas, and the first determining device comprises: second determining means, configured to Determining, by the downlink channel transmission matrix and the downlink data stream, an equivalent matrix of the downlink channel transmission matrix, where the equivalent matrix is a two-dimensional matrix of mx N _t ;

第三确定装置，用于根据所述等效矩阵、所述下行数据流数、所述空间相关矩阵和所述预定码书来确定所述近似等效矩阵，所述近似等效矩阵为 m x N_t的二维矩阵。 a third determining means, configured to determine the approximate equivalent matrix according to the equivalent matrix, the number of downlink data streams, the spatial correlation matrix, and the predetermined codebook, where the approximate equivalent matrix is mx N A two-dimensional matrix of _t .

14. 根据权利要求 1 3 所述的反馈装置，其中所述第三确定装置用于： 14. The feedback device according to claim 13, wherein the third determining device is configured to:

- 根据以下公式来确定所述近似等效矩阵 - determining the approximate equivalent matrix according to the following formula

其中， ?为所述基站中多个发送天线的空间相关矩阵，表示矩阵的转置，，其中，为所述预定码书

Wherein, is a spatial correlation matrix of a plurality of transmitting antennas in the base station, indicating a transposition of the matrix, wherein, the predetermined codebook

中的码字，为 N_t x m的二维矩阵，表示矩阵的共轭， ab_s(i w:)表示对矩阵 w:中的各个元素进行取模操作， t_race{afo(^ )}表示矩阵 _ab_s(mw;)的迹, |7^1表示矩阵的弗罗贝尼乌斯范数，为所述等效矩阵； The codeword in , is a two-dimensional matrix of N _t xm, represents the conjugate of the matrix, ab _s (iw:) represents the modulo operation of each element in the matrix w:, t _race {afo(^ )} represents the matrix The trace of _a b _s (mw;), |7^1 represents the Frobenius norm of the matrix, which is the equivalent matrix;

其中，所述近似等效矩阵的相关信息包括所述码字 ^的下标 k，所述信息反馈装置用于： The information about the approximate equivalent matrix includes a subscript k of the codeword ^, and the information feedback device is used to:

1 5. 一种在无线通信网絡的基站中用于对待发送至用户终端的下行数据进行预编码的预编码装置，包括： A precoding apparatus for precoding a downlink data to be transmitted to a user terminal in a base station of a wireless communication network, comprising:

接收装置，用于接收来自所述用户终端的从所述基站至所述用户终端的下行信道传输矩阵的一个近似等效矩阵的相关信息； a receiving device, configured to receive, by the user equipment, related information of an approximate equivalent matrix of a downlink channel transmission matrix from the base station to the user terminal;

第四确定装置，用于基于所述近似等效矩阵的相关信息、预定码书和所述基站中多个发送天线的空间相关矩阵来确定所述近似等效矩阵； a fourth determining means, configured to determine the approximate equivalent matrix based on correlation information of the approximate equivalent matrix, a predetermined codebook, and a spatial correlation matrix of a plurality of transmit antennas in the base station;

编码装置，用于利用所述近似等效矩阵对待发送至所述用户终端的下行数据进行预编码。 And an encoding device, configured to perform precoding on downlink data to be sent to the user terminal by using the approximate equivalent matrix.